The present invention relates to a photoresist stripping composition and to a process for stripping photoresist, and more particularly, to a stripping composition for removing photoresist film in the production of semiconductor elements and liquid crystal display elements, and to a process for stripping photoresist.
Semiconductor elements have been produced by the steps of applying a photoresist to an inorganic substrate; forming a pattern of the photoresist through exposure to light and subsequent development; etching the region of the inorganic substrate which has not been masked by use of the photoresist pattern as a mask, to thereby form minute circuits; and removing the photoresist film from the inorganic substrate. Alternatively, after forming minute circuits in the same manner, the photoresist pattern is ashed, and then the remaining resist residue is removed from the inorganic substrate.
In recent years, LCDs (liquid crystal displays), inter alia, TFT-LCDs (thin-film transistor liquid crystal displays), are coming to have a larger substrate size, raising problems caused by nonuniformity in film formation of circuit-forming materials, insulating materials, and resist materials as well as uneven exposure, development, and etching, and resulting in increased rate of defective products.
In particular, the nonuniformity in formed film causes generation of dust by exfoliation of the formed film during wet-etching, or generation of dust originating from a resist residue during dry-etching. Such dust cannot be removed during stripping of a resist even by use of a photoresist stripping solution. In some cases, the unremoved dust causes unsatisfactory bonding of thin film formed in the subsequent step. Thus, the nonuniformity in photoresist film finally results in defective products.
In connection with conventional methods for stripping photoresist after dry-etching the above thin films, the Japanese Patent Applications Laid-Open (kokai) Nos. 62-49355, 62-95531, 64-981949, 64-81950, and 5-273768 disclose photoresist stripping solutions containing amino alcohol. However, these photoresist stripping solutions exert no effect of removing dust or similar matter generated during etching.
Thus, an object of the present invention is to provide a photoresist stripper which is capable of easily removing photoresist film formed on an inorganic substrate, photoresist residues, and dust or similar matter generated during etching process in the production of liquid crystal display elements or semiconductor elements, and which is highly anticorrosive to various materials such as semiconductor layer materials, conductive materials, and insulating materials. Another object of the present invention is to provide a process for stripping photoresist.
The present inventors have carried out extensive studies in order to solve the aforementioned problems involved in conventional techniques, and have found that a photoresist stripping composition comprising (a) an alkanolamine other than those alkanolamines falling under the definition of the below-described component (b); (b) an alkanolamine having in the molecule thereof at least one moiety represented by the following formula (1): 
(wherein each of R1 and R2 represents hydrogen or a methyl group, and R4 represents a C1-C5 alkyl group); (c) an amide solvent or a sulfoxide solvent; (d) a phosphorus-containing compound; (e) an oxycarboxylic acid; and (f) water, can completely remove photoresist thin film, photoresist film, photoresist residues, and dust or similar matter generated during an etching process, at low temperatures and over a short period of time without causing corrosion of the materials. The present invention has been accomplished on the basis of this finding.